A. Field of the Invention
This invention relates to a charging system test apparatus and, more particularly, to a system for detecting the malfunctioning and defective circuit elements of an automotive, alternator-battery, electrical system by analyzing the filtered and unfiltered output from the alternator and the voltage level at the output of the alternator under certain conditions.
B. Description of the Prior Art
With the advent of the alternator-battery charging systems in lieu of the generator-battery charging systems, a need has arisen for an apparatus for testing the various components of the alternator-battery charging system. The basic difference between the alternator and generator is the fact that a generator produces direct current which is regulated and fed to the electrical system of the vehicle and to the battery for charging purposes. The alternator, on the other hand, produces alternating current which is rectified by a diode rectifying system to produce pulsating direct current which, in turn, is fed to the electrical system and battery for charging purposes. Accordingly, it is necessary to provide a test system which will not only test the battery condition but also will test the condition of the diodes, the alternator field, and the regulator system.
Systems have been previously evolved for testing the condition of various elements within the automotive electrical system. However, the majority of these systems require a plurality of selective connections to various elements in the charging circuit between the alternator and the battery, including the regulator circuit. Such systems require a certain degree of skill on the part of the operator to properly select the connections to be made and to be able to properly correlate the output reading encountered with the readings expected under normal operation. Even at this point, the operator requires skill to make a determination as to which components of the alternator-battery system are malfunctioning.
Further, these prior systems are, in certain circumstances, of the type which require actual interruption of the vehicle wiring. Accordingly, further skill is required in knowing which wires to remove and reconnect to insure proper operation of the test system. Additionally, certain of these systems require a separate power supply from that within the automobile. Accordingly, these separate supply systems must be plugged into a convenience outlet or a direct current supply included within the apparatus. These systems are inconvenient to use if a convenience outlet is not available and, in the case of a battery supply, require constant changing of batteries and testing of batteries within the system to ensure that the voltage level of the power supply is sufficient before the tests are conducted.
A further system for testing an alternator-battery charging system has been provided in the prior art which includes an apparatus for analyzing the waveform and magnitude of the ripple voltage superimposed on the alternator output, which ripple characteristics are indicative of whether or not the alternator is operating normally. Circuitry is provided to energize indicator lights in responsive to certain detected ripple characteristics, thereby providing an unambiguous indication of the operational status of the alternator. Further, circuitry is provided to sense the voltage at the alternator field terminal to determine if malfunctioning of the voltage regulator is present. This system is disclosed in United States Letters Patent 3,629,704, patented Dec. 21, 1971.